Most people who switch to a zinc-based deodorant get exactly what they came for. But a small number find the opposite, it seems to do nothing, or they smell worse on it than off it. If that's you, you're not imagining it, and there's a real explanation.
Everyone's underarm bacteria are different. Zinc fits the large majority, but a small number have a chemistry it doesn't match. The fix isn't giving up, it's switching to a different mix of actives.
The microbiome mismatch
Your armpit hosts a personal mix of bacteria, and that mix varies a lot from person to person. Zinc-based odor control works by acting on the specific bacterial and chemical processes that produce odor in most people. It's effective across the large majority because most people's underarm chemistry responds to it.
But a minority have a microbiome composition or skin chemistry that doesn't respond the way the average does. In those cases, a zinc system can underperform, and occasionally, the shift in the bacterial balance can read as worse odor rather than better, at least for that individual.
What to do if you're one of them
The answer isn't to give up on natural deodorant. It's to change the mix, try a formula that comes at odor from a different direction, because where one combination mismatches your chemistry, another may fit it well.
That's a real reason Zaffré makes more than one kind of formula. If our zinc-led formulas, Max and Sensitive, don't agree with your particular chemistry, Tea Tree is the one to try next. It keeps zinc but leads with tea tree and sage instead of the supporting actives the other two use, so the whole character of the formula is different. It works on feet as well as underarms.
Not sure where to go next? The buyer's guide lays out all three formulas.